When to Replace the 12 volt battery?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by theborghomeworld, Sep 24, 2009.

  1. theborghomeworld

    theborghomeworld New Member

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    Hey All!
    Gotta question about when to replace a 12 volt battery (for future reference). A few months ago, when I turned off my prius, it didn't turn off but went into acc mode. I suspected the 12 volt battery was about to go.

    Since then, I haven't had any new symptoms, but I finally decided to replace the battery at my 45k oil change. I've had the car for about 38 months or so now (bought new).

    The dealer did a load test, which I've attached. But since the picture is blurry, I'll type out the results below.

    RESULTS
    REPLACE BATTERY
    Rated CCA: 356
    Measured CCA: 131
    Measured volts: 12.47
    Degrees F: 91
    Warranty Code: A93P
    State of Charge: (Diagram shows about 60%)
    State of Health: (Diagram shows about 35%)

    But not to always trust a dealer's recommendation, what criteria would you use when replacing a battery?

    Thanks!
    Andrew
     

    Attached Files:

    #1 theborghomeworld, Sep 24, 2009
  2. Sandy

    Sandy Hippi Chick

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    Mine was 5.5 years I started having starnge issues with it not starting then I could not shut her down, as soon as i changed it all is back to normal, I had a bad cell and paid 138.00 from my dealer :)
     
    #2 Sandy, Sep 24, 2009
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Andrew,

    I'm a bit surprised that your 12V battery needed replacement after three years considering you drive the car a lot (15K miles per year, which means the car is driven enough so that the battery should remain fully-charged) and you live in an area with moderate weather. Normally I would think the battery would last 5-6 years under those conditions.

    Nevertheless, since you were starting to note weird behavior, and assuming you would be inconvenienced by a no-start situation, then it was reasonable to replace the battery now.
     
    #3 Patrick Wong, Sep 24, 2009
  4. richard schumacher

    richard schumacher shortbus driver

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    That one thing a few months ago was the only symptom? I'd bet that the contact bounced or that you hit the button twice, and that there was nothing wrong with the battery. 12.5V under a heavy load is a good battery.
     
    #4 richard schumacher, Sep 25, 2009
  5. theborghomeworld

    theborghomeworld New Member

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    yeah, that was the only symptom I noticed. pretty sure i didn't hit it twice, but could have happened.

    also, i left the dome light on overnight only once. the car started up fine the next day.

    richard, do you use voltage to tell you when to change the battery, say if it drops below 11 volts?

    thanks for the input so far!
    andrew
     
    #5 theborghomeworld, Sep 25, 2009
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